Hydrojet power unit for boats with power reverse propulsion



Jan. 7, 1964 c. J. DAHLE 3,116,602

HYDROJET POWER UNIT FOR BOATS WITH POWER REVERSE PROPULSION Filed May 8,1961 4 Sheets-Sheet 1 INVENTOR. Charles J Duh le A75 Us.

C. J. DAHLE HYDROJET POWER UNIT FOR BOATS WITH POWER REVERSE PROPULSIONFiled May 8. 1961 4 Sheets-Sheet 2 INVENTOR. Char/es J. Dab/e M FW-III-II Jan. 7, 1964 c, DAHLE 3,116,602

HYDROJET POWER UNIT FOR BOATS WITH POWER REVERSE PROPULSION Filed May 8,1961 4 Sheets-Sheet 3 INVENTOR. Char/es I Dah/e Aizjys.

Jan. 7, 1964 c. J. DAHLE 3,116,602

HYDROJET POWER UNIT FOR BOATS WITH POWER REVERSE PROPULSION Filed May a,1961 4 Sheets-Sheet 4 NVENTOR.

I Char/es a." Doh/e United States Patent 3,116,602 HYDROJET POWER UNITFOR BOATS WITH POWER REVERSE PROPULSION Charles J. Dahle, Salmon, IdahoFiled May 8, 1961, Ser. No. 108,558 1 Claim. (Cl. 6035.54)

This invention relates to a hydrojet power unit for boats and includes areversing power system.

The present invention is an improvement over the propulsion and steeringunit described in my co-pending appiication, now Patent No. 3,040,696,granted June 26, 1962, for Propulsion and Steering Unit for Boats. Inthat application was shown a practical version of a hydrojet unitwherein water was taken in along the keel line of the boat and forciblyejected in a rearward direction through the transom to provide a drivingforce for the boat. In this prior application is shown a pair of fullcircle auger impeller units which are used to drive the water through acylindrical shell. tion contemplates an improved form of impeller bladesto be used in this earlier combination. It also contemplates revision ofthe fixed guide vanes which limit movement of the water to an axialdirection. It further adds a reverse power unit so as to enable theoperator of the boat to operate it in a reverse direction and to steerthe boat while utilizing this reverse operation.

It is a first object of this invention to provide a novel impeller bladefor use in this combination, which blade will better utilize the twostage impeller system desired in this unit. In order to accomplish thisobject smaller arcuate blades are used in the impeller unit adjacent thewater intake than are used in the second stage impeller unit placedrearwardly of the first unit. In this way water is allowed to be pulledpast the first unit by the action of the blades in the second impellerunit.

It is another object of the present invention to provide a blade havingan improved profile which increases the efiiciency and lessens theturbulence of the water being pulled through the hydrojet unit.

It is another object of this invention to provide a reversible powerunit adapted to be mounted on the hydrojet unit so as to enable theoperator to reverse the direction of the exhausted water so as to drivethe boat in a reverse direction.

Another object of the invention is to provide such a reversing drivewhich can be operated by a single control lever. The controls for thereverse drive further includes steering controls linked with the normalboat steering mechanism. The steering of the boat in reverse drive isthus identical to the operation involved in normally steering the boatin a forward direction.

These and further objects will be obvious from a study of the followingdisclosure which illustrates a preferred improved form of the invention.It is to be understood that this form is merely exemplary andillustrates the invention while not limiting or defining it. Theinvention is to be restricted only by the disclosure of the claim whichfollows.

In the drawings,

The present inven- 3,116,602 Patented Jan. 7, 1964 FIGURE 7 is a sideelevational view of the boat seen in FIGURE 1;

FIGURE 8 is a sectional view through an impeller blade taken along line8-8 in FIGURE 3;

FIGURE 9 is another sectional view through an impeller blade as seenalong line 9-9 in FIGURE 3;

FIGURE 10 is a projected view along an arcuate line shown as 10-10 inFIGURE 3 and designed to show the relative curvatures of the bladesurfaces;

FIGURE 11 is a fragmentary top view of the reversing unit as seen inFIGURE 1 with the unit in position for reverse drive of the boat;

FIGURE 12 is a view similar to FIGURE 11 with the drive control in aneutral position; and

FIGURE 13 is a fragmentary top view of the rudder and reversingassembly, showing the steering control utilized in reverse drive.

This invention relates to several improvements formulated with regard tothe propulsion unit shown and described in detail in my above citedpending application. The basic operation of the unit remains identicalto that described in this earlier description. Many parts of the unitremain unchanged and will not be described in further detail herein. Thepresent invention reflects improvements in the impeller blades, in theguide vanes, in the tail bearing structure and in the directionalcontrol for the unit. In the last instance, a totally new reversingmechanism has been added to the unit which was previously only usable ina forward direction.

Referring now to FIGURES 1, 2, 6 and 7, the general scheme of the unitwill be described. The propulsion unit is shown mounted upon a boat hull10, including the bottom 11, adjacent sides 12 and the vertical reartransom 13. The propulsion unit itself is mounted within a cylin dricalmetal housing 14 which is positioned in a longitudinal direction alongthe keel of the boat. Mounted at the rear of the cylindrical housing 14and forming a part thereof is a nozzle section 15. The nozzle section 15is suitably fastened to the main body of the housing 14 and protrudesthrough a sealed aperture cut through the transom 13 so as to extendbeyond the normal length of boat hull 10. At the forward end of thehousing 14 is mounted a grill box 16, identical to that previously shownin my co-pending application. The grill box 16 is adapted to be securedfrom the exterior of the boat and is sealed within an aperture cutthrough the bottom 11. The box 16 is hydraulically opened to the forwardsection of the housing 14 and is suitably fastened thereto. Thus waterdrawn through the grill box 16 can be passed through the housing 14,including the nozzle section 15, and can be ejected through the openrear end of the nozzle section 15 to thereby propel the boat hull 10 ina forward direction.

Rotatably mounted within the housing 14 is an axial impeller shaft 17.The shaft 17 extends forwardly beyond the housing 14 and may be suitablydriven by a con- FIGURE 1 is a top view of the rear section of a boatventional motor equipped with or without a clutch or transmission, asmay be desired. The shaft 17 is rotatably journalled by front bearings.18 which are exteriorly mounted on the front end of the housing 14. Thebearings 18 are sealed from the interior of the housing 14 by a suitablepacking gland 20. Mounted at the opening from the grill box 16 and fixedrelative to the impeller shaft 17 are two blades 21 which form the firstimpeller unit. These blades 21 are formed on a hub 22 which is suitablykeyed to the shaft 17 so as to rotate as a unit therewith. The blades 21are spiral auger blades, each of which transcribes an arc having a totalarcuate distance of less than degrees. These blades can be seen inFIGURE 3. Thus water can be drawn between the two blades 21, althoughthe majority of water area encountered by blades 21 will be axiallypushed thereby. Mounted directly rearward of the first blades 21 are apair of second blades 23 which form the second impeller unit. The blades23 are formed on a hub 24 which also is suitably keyed to the shaft 17.The are circumscribed by each of the blades 23 is greater than thatcircumscribed by the blades 21. This may be seen in FIG- URE 4. Each ofthe blades 23 is almost 180 degrees about the center of shaft 17 so thatsubstantially all the water area encountered by blades 23 is axiallymoved along the longitudinal direction of the cylindrical housing 14.

Interposed between the blades 21 and the blades 23 is a first stationaryguide vane unit. The guide vanes 25 are formed within an outer ring 25aand an inner ring 25b. The two rings 25a and 25b are split so as to bepositioned about the shaft 17. The outer ring 25a is secured to thehousing 14 by any suitable means such as welding or releasable bolts.Mounted directly rearward of the second blades 23 is a second set ofguides 26. The guide vanes 26 extend in a radial manner similar to theguide vanes 25. The final guide vanes 26 are bounded by an outer ring26a and an inner ring 26b, within which the tail bearings 28 are housed.The tail bearings 28 are mounted within a sealed grease housing 27 whichtapers rearwardly so as to lessen water turbulence. The tail bearings 28serve to rotatably position the rear end of the impeller shaft 17 and toaccurately position the two sets of blades 21 and 23 within the housing14.

.The contour of the blades 21 and 23 is extremely important. Theseblades contours must be formed so as to minimize avater turbulence whileproviding an effective axial push on the volume of water transmittedthrough the housing 14. In order to accomplish these results the bladecontours are formed as shown in FIGURES 8 through 10. Each blade 21 or23 has a vertical rear surface 21a or 23a. This surface is spiralledabout the axis of shaft 17 to the desired arcuate extremes. Each blade21-23 also includes a tapered forward surface 21b or 23b. These surfacesare tapered outwardly from the hubs 22 or 24 to form a relatively thinouter radial edge adjacent the interior surface of the housing 14. Thethickness of the blades 2 1-23 also decreases arcuately from theirarcuate centers to their outer radial edges. This can be seen in FIGURE10' which illustrates the fact that the forward surface 21b of a blade21 has a greater convexity relative to the concavity of the rear surface21a. Thus the blades 2123 are formed with thick central hub areas whichtaper both radially and arcu-ately to their extreme edges which areformed in a quite thin fashion. This blade form reduces turbulence inthe water by providing a relatively thin meeting edge which extends to astrengthened middle blade area for maximum strength, while also servingfurther to compress water pushed by the rotating blades 21 and 23.

The fact that the first blades 21 are less long circumferentially thanthe second blades 23 provides additional thrust in the unit as a whole.The blades 23 can thus draw the water past the first blades 21 tothereby add to the total thrust exerted on escaping water ejectedthrough the nozzle section 15. Thus both blades 21 and both blades 23are fully utilized to move a total volume of water through the interiorof the housing 14. This actually reduces the incidence of vacuum pocketsforming within the housing 14 and reduces turbulence throughout theentire unit.

Normal forward steering of this unit is provided by a rudder 30 whichextends partially within the nozzle section 15. The rudder 30 is fixedto a rudder post 31 rotatably journalled on the nozzle section 15. Thepost 3-1 is moved by means of a crank arm 29 and by a control cable 32which is suitably moved from the interior of the boat hull 10. Inforward operation the rudder 30 is maintained in a straight longitudinalposition as shown in FIGURE 1. To turn the boat in either direction thecable 32 is moved to pivot the rudder post 31 and thereby block aportion of the nozzle section 15 and deflect the remaining water volumeejected through the housing 14 and nozzle section 15. This portion ofthe steering arrangement is identical to that described in my co-pendingapplication. 1

Since the instant unit is designed primarily for use in rivers andshallow locations where a low total draft is desirable, themaneuverability of the boat hull 10 is further enhanced by the provisionof a reversing mechanism. .Il'l order to accomplish this result theinstant unit is shown provided with a perpendicular tube 33 fixed to theforward end of the nozzle section 15 and open thereto. The tube 33 isformed integrally with a pair of forward projecting extensions 34 and 35which open to apertures 36 and 37 sealed through the sides 12 of theboat on either side adjacent the housing 14. Thus water ejected throughthe tube 33 will be directed outwardly to the apertures 36 and 37 in asusbtantially forward direction to thereby propel the boat hull 10 in arearward direction.

The control of Water flow through the nozzle section '15 and tube 33 isgoverned by three vertical butterfly valves. A central large valve 38 ismounted in the nozzle section .15 directly rearward of the opening oftube 33 to the nozzle section 15. The valve 38 is fixed to a pivot shaft40 which in turn is suitably journalled for rotation about a verticalaxis by the nozzle section 15. The two sides of tube 33 are selectivelysealed by side valves 41, 42, which are respectively fixed on pivotshafts 43, 44 which in turn are rotatably mounted by the tube 33 forrotation about vertical axes. Thus closing of the valves 41, 42 willprevent entry of water into the tube 33, while closing of the valve 38will prevent the issuance of water through the nozzle section 15.

:In order to interrelate the positions of these three valves 38, 41 and42, a combined control system is provided. The pivot shaft 40 isprovided with a crank arm 45 at the top end thereof and the two pivotshafts 43 and 44 are respectively provided with crank arms 46 and 47.These three arms 45, 46 and 47 are pivotally joined by a commonconnecting link 50. The connecting link 50 can thus rotate all threevalves 38, 41 and 42 simultaneously. An operating arm 48 is fixed to thecrank arm 46 and provides the necessary leverage for remote movement ofthe three pivot shafts 40, 43 and 44. The arm 48 is moved by a suitableoperating rod 51 which is connected to its outer end. The operating rod51 extends forwardly along the boat hull 10 to any suitable conventionalmechanism adapted to reciprocate it in a longitudinal direction. Anycommon lever system would .be suitable. The rod 51 is shown in 'FIGURE 1in its forward position with the valve 38 wide open and the two sidevalves 41 and 42 completely closed. Thus the total volume of water movedthrough the housing 14 will be ejected through the nozzle section 15. Atthe opposite extreme is the condition shown in FIGURE 11 wherein valve38 has been closed and valves 41 and 42 have been opened by rearwardmovement of the rod 51. in this condition no water will be ejectedthrough the nozzle section 15 and the total water volume will be ejectedthrough the side apertures 36 and 37. Between these two extremepositions the rod 51 may be positioned as desired so as to modulate theboats speed or to provide a neutral condition by partially opening allthree valves 38, 41 and 42. Such a neutral position is illustrated inFIGURE 12, with the rod 51 in a position intermediate that shown inFIGURE 1 or 11.

In order to further add to the maneuverability of a boat equipped withthis propulsion unit, reverse steering has been provided in theillustrated embodiment. This steering is accomplished by a pair of sidesteering valves 52 and 53, positioned adjacent the side valves 41 and 42respectively within the tube 33. The valves 52 and 53 are identical instructure to the valves 41 and 42 and are fixed to pivot shafts 54 and55 respectively. The

shafts 54 and 55 are capped by two crank arms 56 and 57. The two arms 56and '57 are biased against stops 62 and 63 by tension springs 58 and 60respectively. The remaining ends of the springs 58 and 60 are fastenedto the top center of the housing 14. The stops 62 and 63 are fixed tothe outer surface of the tube 33. Thus the springs 58 and 60 maintainthe two steering valves 52 and 53 in a normally fully open position. Thetwo crank arms 56 and 57 are connected to the rear end of the rudder arm29 by means of a cable 61 which is threaded through the transom 13 andguided by pulleys 64. As can be seen in FIGURE 13 the valves 52 and 53are operated in conjunction with the rudder 30 by the control cable 32.In FIGURE 13 the control cable 32 is shown in a position which wouldnormally direct the boat to the right in a forward direction in theabsence of the reverse propulsion means described above. With the valve38 opened and the boat being projected in a forward direction the valves52 and 53 would operate but would be of no importance since no waterwould be flowing past the side valves 41 and 42. If the valves 41 and 42are opened, as when the boat is being driven in a reverse direction,movement of the rudder 30 will close one of the valves 52 or 53 andthereby restrict the flow of water through one of the extensions 34 or35. This will propel the boat to one side or the other. The direction oftravel will be opposite to that attained during forward drive. However,the turning moment exerted on the boat hull will be the same so thatmovement of the boat will not be resisted by the rudder 30. The valves52 and 53 will operate in conjunction with the rudder 30 to provide atotal steering control during intermediate positioning of the rod 51between the neutral position shown in FIGURE 12 and the two extremepositions shown in FIGURES 1 and 11.

Thus the improved hydrojet unit described in the above specificationprovides a more eflicient impeller mechanism at a lower cost due to thesavings in materials over a full 360 degree arbor blade. It alsoprovides a greater efliciency and load distribution between the twoimpeller units. It reduces turbulence and increases the volume capacityof the impeller units. The hydrojet unit also embodies a workablereversing drive, utilizing a simple mechanism to great advantage. Thereversing mechanism shown is particularly well adapted for the hydrojetunit as described and combines therewith to provide a fully maneuverablepower and steering unit. Various modifications may occur to one skilledin this field without deviating from the basic concepts described above.For this reason the invention is to be limited only by the followingclaim.

Having thus described my invention, I claim:

In a propulsion unit for boats having a cylindrical housing mounted onthe boat hull with a water inlet formed through the hull in connectionwith the forward end of said housing, said housing including a rearnozzle extending through the boat transom, and impeller means mountedwithin said housing:

a reversing mechanism, comprising:

a pair of hollow tubes opening to said housing rearward of said impellermeans and forward of the nozzle opening, each of said tubes extendingtransversely from said housing and terminating in a forwardly directedopening formed through the boat hull above the water line adjacent saidhousing and at each side thereof;

a first butterfly valve located Within said housing rearwardly of theopenings of said tubes to said housing, said first valve being adaptedto selectively prevent flow of water through said nozzle;

second and third butterfly valves located respectively within said pairof tubes adjacent said housing, said second and third valves beingadapted to selectively prevent flow of water through said tubes;

a manual control linking said first, second and third valves adapted tosimultaneously operate said valves to selectively open said first valveand close said second and third valves or to close said first valve andopen said second and third valves, or to attain an intermediate settingof the three valves between these two extreme conditions;

fourth and fifth butterfly valves located respectively within said pairof tubes;

and control means linking said fourth and fifth valves to the boatsteering controls whereby operation of the steering controls willselectively restrict flow of water through one of said pair of tubes andincrease flow through the remaining tube.

References Cited in the file of this patent UNITED STATES PATENTS340,237 Nagel et al. Apr. 20, 1886 514,527 Wauters Feb. 13, 1894 849,030Valliquette Apr. 2, 1907 2,024,274 Campini Dec. 17, 1935 2,706,451Mayer-Ortiz et a1 Apr. 19, 1955 2,944,393 Fox July 12, 1960 2,993,463McKinney July 25, 1961 3,078,661 Spence Feb. 26, 1963 OTHER REFERENCESRobberson: Water-Jet Propulsion, Yachting Magazine, November 1959, pp.-71 (vol. 106, No. 5).

